Scanning display device

Abstract

The purpose of the present invention is to provide a laser scanning display device capable of achieving high-resolution projection display while ensuring that the luminance and the size of the pixels are uniform to maintain the quality of the projection display. The scanning display device is configured to apply noise from a dither noise generator ( 21 ) to a horizontal scanning position on an oscillating mirror ( 11,12 ) determined by a scanning position determination unit ( 13 ); normalize the horizontal scanning position to which the noise was applied using a normalizing unit ( 22 ); acquire a pixel address corresponding to the normalized horizontal scanning position by referring to a pixel address table ( 23 ); read pixel data corresponding to the pixel address from an image memory ( 14 ); and modulate laser light by driving a light source ( 17 ) for emitting the laser light.

The invention claimed is: 
     
       1. A scanning display device configured to project laser light modulated with image data by an oscillation mirror for scanning in vertical and horizontal directions, comprising:
 an image memory for storing the image data; 
 a scanning position determination unit for determining vertical and horizontal scanning positions of the oscillation mirrors; 
 a laser control unit for acquiring a pixel address corresponding to the scanning positions determined by the scanning position determination unit and reading pixel data in the image data corresponding to the pixel address from the image memory; and 
 a light source control drive unit for driving a light source to emit the laser light modulated with the pixel data read from the image memory to the oscillation mirror, 
 wherein the laser control unit includes: 
 a dither noise generator configured to generate normalization noise, 
 a normalizing unit for adding the normalization noise to normalize a time address corresponding to the horizontal scanning position of the oscillation mirror, which has been determined by the scanning position determination unit, and outputting the normalized time address to which the normalization noise is added, and 
 a pixel address table which holds a plurality of pixel addresses including the pixel address, and 
 wherein the pixel address corresponding to the normalized time address is acquired in reference to the pixel address table to read the pixel data corresponding to the pixel address in the image data from the image memory. 
 
     
     
       2. The scanning display device according to  claim 1 , wherein the normalization noise is generated by the dither noise generator corresponding to the vertical scanning position of the oscillation mirror. 
     
     
       3. The scanning display device according to  claim 1 , wherein:
 the dither noise generator is further configured to generate reference noise, and 
 the pixel address corresponding to the normalized time address, to which the reference noise is added, is acquired from the pixel address table to read the pixel data corresponding to the pixel address in the image data from the image memory. 
 
     
     
       4. The scanning display device according to  claim 3 , wherein the dither noise generator is configured to generate the normalization noise and the reference noise according to the vertical and horizontal scanning positions and a frame period of the image data. 
     
     
       5. The scanning display device according to  claim 4 , wherein:
 at least one of the normalization noise or the reference noise includes two or more noise modes; and 
 the noise modes are switched for each horizontal scanning period or each vertical scanning period of the image data. 
 
     
     
       6. The scanning display device according to  claim 1 , further comprising:
 a mirror drive unit and a mirror control unit configured to execute a PLL control so that the oscillation mirror constantly retains a maximum oscillation angle. 
 
     
     
       7. The scanning display device according to  claim 6 , wherein:
 a control accuracy of the mirror control unit is higher than that for resolving a display resolution by twice or more; 
 a normalizing accuracy of the normalizing unit is higher than that for resolving the display resolution by twice or more; and 
 an accuracy of the pixel addresses of the pixel address table is higher than that of the display resolution by twice or more. 
 
     
     
       8. A scanning display device configured to project laser light modulated with image data by an oscillation mirror for scanning in vertical and horizontal directions, comprising:
 an image memory for storing the image data; 
 a scanning position determination unit for determining vertical and horizontal scanning positions of the oscillation mirrors; 
 a laser control unit for acquiring a pixel address corresponding to the scanning positions determined by the scanning position determination unit and reading pixel data in the image data corresponding to the pixel address from the image memory; and 
 a light source control drive unit for driving a light source to emit the laser light modulated with the pixel data read from the image memory to the oscillation mirror, 
 wherein the laser control unit includes: 
 a dither noise generator configured to generate noise, 
 a normalizing unit for adding the noise generated by the dither noise generator to the horizontal scanning position of the oscillation mirror, which has been determined by the scanning position determination unit, and outputting the normalized horizontal scanning position to which the noise is added, and 
 a pixel address table which holds a plurality of pixel addresses including the pixel address, and 
 the pixel address corresponding to the horizontal scanning position normalized by the normalizing unit is acquired in reference to the pixel address table to read the pixel data corresponding to the pixel address in the image data from the image memory, 
 wherein, in the case where the referred display pixel address is positioned between adjacent pixels, both pixel data of the adjacent pixels are read from the image memory, and interpolation is executed in accordance with a center of gravity between the adjacent pixels. 
 
     
     
       9. The scanning display device according to  claim 1 , wherein:
 the image memory stores the image data of three primary colors of red (R), green (G), and blue (B); and 
 the light source includes three laser light sources of red (R), green (G), and blue (B) light modulated with the image data read from the image memory to the oscillation mirror.